Dental caries remains a prevalent and chronic oral disease affecting children globally (Kanasi et al., 2010, Kusuma et al., 2017). According to the World Health Organisation, approximately 60–90% of school-aged children are affected by dental caries, with significantly higher prevalence observed in low- and middle-income countries due to poor oral hygiene and limited access to preventive care (Saekel, 2016). One of the primary causative agents of dental caries is Streptococcus mutans (S mutans), a Gram-positive bacterium that colonises tooth surfaces and ferments dietary carbohydrates, leading to acid production, enamel demineralisation, and subsequent plaque formation (Gong et al., 2021, Kanasi et al., 2010). The formation of biofilm, commonly referred to as dental plaque, involves two distinct stages: an early stage where bacterial cells attach reversibly to the tooth surface, and a subsequent stage of strong, irreversible adhesion that is highly dependent on sucrose. This latter stage is mediated by glucosyltransferases, which synthesise glucan, a critical component for bacterial colonisation and biofilm maturation (Mandava et al., 2019). These mechanisms are critical in the initiation and progression of dental caries, particularly in paediatric populations with developing dentition and dietary habits that promote plaque accumulation.

In recent years, plant-based antimicrobials have gained attention as natural, safe, and effective alternatives to synthetic oral antiseptics such as chlorhexidine, which may cause tooth discoloration and mucosal irritation upon prolonged use (Abachi et al., 2016, Furiga et al., 2008, Mandava et al., 2019). Plant extracts and their constituents have been shown in earlier research to have strong antibacterial action against oral bacteria, particularly Streptococcus mutans such as Ocimum sanctum L. (Kalra et al., 2019, Pai et al., 2022), Ocimum tenuiflorum (Shivakumar et al., 2022), Althaea officinalis root extract (Haghgoo et al., 2017), Piper crocatum (Hartini and Nugroho, 2020, Heliawati et al., 2022), infusion of fruit peels Garcinia mangostana L. (Widyarman et al., 2019), extract methanol Citrus aurantifolia (Haghgoo et al., 2017), and Persea americana seeds (Sugiaman et al., 2023). These effects are largely attributed to bioactive phytochemicals such as flavonoids, tannins, phenolic acids, and saponins, which interfere with bacterial adhesion, disrupt membrane integrity, and inhibit enzyme activity essential for biofilm formation (Adamczak et al., 2019, Farhadi et al., 2019).

Among these, Piper betel L. (PB), commonly used in traditional medicine across Southeast Asia, has shown promise due to its rich content of eugenol, chavicol, hydroxychavicol, and flavonoids, known for their antimicrobial, anti-inflammatory, and antioxidant properties (Tenda et al., 2017, Kurek-Górecka et al., 2022). Ethnomedicinally, Piper betel has been used for treating oral ulcers, halitosis, and wound infections, supporting its relevance in dental therapeutics. However, despite growing evidence on its antimicrobial potential, limited studies have explored its integration into pharmaceutical dosage forms, particularly lozenges (Adamczak et al., 2019, Farhadi et al., 2019, Gong et al., 2021, Kusuma et al., 2017).

Lozenges offer several advantages over other oral delivery systems: they ensure prolonged contact time in the oral cavity, improve patient compliance (especially among children), and allow for local drug release with minimal systemic absorption (Nithya, 2019). Furthermore, they are easier to administer than mouthwashes or ointments in paediatric settings and can be formulated with palatable flavours. While in vitro studies have shown the antibacterial activity of Piper betel extract, there remains a gap in translating this potential into clinically viable formulations with validated physicochemical characteristics and delivery performance. Thus, a scientifically robust formulation of Piper betel lozenges and evaluation of its antibacterial efficacy against S mutans is warranted. The hypothesis of this study is PB leaf extract can be effectively formulated into lozenges that exhibit significant antibacterial activity against Streptococcus mutans while maintaining acceptable pharmaceutical quality standards. This study aims to evaluate the antimicrobial activity of Piper betel leaf extract against S. mutans and develop and assess lozenge formulations incorporating the extract, focusing on both microbiological efficacy and pharmaceutical quality.